Any multi-tenant environments on an affected version using CRM integration should implement NAV 2016 CU 15.1 or NAV 2017 CU 2.1 as soon as possible as a precautionary measure.

Customers on Dynamics 365 for Financials do not need to take any action; this issue has been corrected in all available versions.

NAV 2016 CU 15.1 and NAV 2017 CU 2.1 will be released as soon as possible

Lost of people, including myself, managed to download CU2 before it was pulled, and I have now seen several places where people are putting it up for download. Apart from the obvious reason of my distributing other people’s software, aka piracy, CU2 should not be used in a production environment and you should never trust Dynamics NAV pulled from somebody’s OneDrive, Dropbox or any source but Microsoft Download Center.